forked from llvm/llvm-project
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[libc][math][c23] Add exp2m1f16 C23 math function (llvm#105690)
Part of llvm#95250.
- Loading branch information
1 parent
fb0f207
commit c77bb23
Showing
14 changed files
with
410 additions
and
42 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,21 @@ | ||
| //===-- Implementation header for exp2m1f16 ---------------------*- C++ -*-===// | ||
| // | ||
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | ||
| // See https://llvm.org/LICENSE.txt for license information. | ||
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | ||
| // | ||
| //===----------------------------------------------------------------------===// | ||
|
|
||
| #ifndef LLVM_LIBC_SRC_MATH_EXP2M1F16_H | ||
| #define LLVM_LIBC_SRC_MATH_EXP2M1F16_H | ||
|
|
||
| #include "src/__support/macros/config.h" | ||
| #include "src/__support/macros/properties/types.h" | ||
|
|
||
| namespace LIBC_NAMESPACE_DECL { | ||
|
|
||
| float16 exp2m1f16(float16 x); | ||
|
|
||
| } // namespace LIBC_NAMESPACE_DECL | ||
|
|
||
| #endif // LLVM_LIBC_SRC_MATH_EXP2M1F16_H |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,162 @@ | ||
| //===-- Half-precision 2^x - 1 function -----------------------------------===// | ||
| // | ||
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | ||
| // See https://llvm.org/LICENSE.txt for license information. | ||
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | ||
| // | ||
| //===----------------------------------------------------------------------===// | ||
|
|
||
| #include "src/math/exp2m1f16.h" | ||
| #include "expxf16.h" | ||
| #include "hdr/errno_macros.h" | ||
| #include "hdr/fenv_macros.h" | ||
| #include "src/__support/FPUtil/FEnvImpl.h" | ||
| #include "src/__support/FPUtil/FPBits.h" | ||
| #include "src/__support/FPUtil/PolyEval.h" | ||
| #include "src/__support/FPUtil/cast.h" | ||
| #include "src/__support/FPUtil/except_value_utils.h" | ||
| #include "src/__support/FPUtil/multiply_add.h" | ||
| #include "src/__support/FPUtil/rounding_mode.h" | ||
| #include "src/__support/common.h" | ||
| #include "src/__support/macros/config.h" | ||
| #include "src/__support/macros/optimization.h" | ||
| #include "src/__support/macros/properties/cpu_features.h" | ||
|
|
||
| namespace LIBC_NAMESPACE_DECL { | ||
|
|
||
| static constexpr fputil::ExceptValues<float16, 6> EXP2M1F16_EXCEPTS_LO = {{ | ||
| // (input, RZ output, RU offset, RD offset, RN offset) | ||
| // x = 0x1.cf4p-13, exp2m1f16(x) = 0x1.41p-13 (RZ) | ||
| {0x0b3dU, 0x0904U, 1U, 0U, 1U}, | ||
| // x = 0x1.4fcp-12, exp2m1f16(x) = 0x1.d14p-13 (RZ) | ||
| {0x0d3fU, 0x0b45U, 1U, 0U, 1U}, | ||
| // x = 0x1.63p-11, exp2m1f16(x) = 0x1.ec4p-12 (RZ) | ||
| {0x118cU, 0x0fb1U, 1U, 0U, 0U}, | ||
| // x = 0x1.6fp-7, exp2m1f16(x) = 0x1.fe8p-8 (RZ) | ||
| {0x21bcU, 0x1ffaU, 1U, 0U, 1U}, | ||
| // x = -0x1.c6p-10, exp2m1f16(x) = -0x1.3a8p-10 (RZ) | ||
| {0x9718U, 0x94eaU, 0U, 1U, 0U}, | ||
| // x = -0x1.cfcp-10, exp2m1f16(x) = -0x1.414p-10 (RZ) | ||
| {0x973fU, 0x9505U, 0U, 1U, 0U}, | ||
| }}; | ||
|
|
||
| #ifdef LIBC_TARGET_CPU_HAS_FMA | ||
| static constexpr size_t N_EXP2M1F16_EXCEPTS_HI = 6; | ||
| #else | ||
| static constexpr size_t N_EXP2M1F16_EXCEPTS_HI = 7; | ||
| #endif | ||
|
|
||
| static constexpr fputil::ExceptValues<float16, N_EXP2M1F16_EXCEPTS_HI> | ||
| EXP2M1F16_EXCEPTS_HI = {{ | ||
| // (input, RZ output, RU offset, RD offset, RN offset) | ||
| // x = 0x1.e58p-3, exp2m1f16(x) = 0x1.6dcp-3 (RZ) | ||
| {0x3396U, 0x31b7U, 1U, 0U, 0U}, | ||
| #ifndef LIBC_TARGET_CPU_HAS_FMA | ||
| // x = 0x1.2e8p-2, exp2m1f16(x) = 0x1.d14p-3 (RZ) | ||
| {0x34baU, 0x3345U, 1U, 0U, 0U}, | ||
| #endif | ||
| // x = 0x1.ad8p-2, exp2m1f16(x) = 0x1.598p-2 (RZ) | ||
| {0x36b6U, 0x3566U, 1U, 0U, 0U}, | ||
| #ifdef LIBC_TARGET_CPU_HAS_FMA | ||
| // x = 0x1.edcp-2, exp2m1f16(x) = 0x1.964p-2 (RZ) | ||
| {0x37b7U, 0x3659U, 1U, 0U, 1U}, | ||
| #endif | ||
| // x = -0x1.804p-3, exp2m1f16(x) = -0x1.f34p-4 (RZ) | ||
| {0xb201U, 0xafcdU, 0U, 1U, 1U}, | ||
| // x = -0x1.f3p-3, exp2m1f16(x) = -0x1.3e4p-3 (RZ) | ||
| {0xb3ccU, 0xb0f9U, 0U, 1U, 0U}, | ||
| // x = -0x1.294p-1, exp2m1f16(x) = -0x1.53p-2 (RZ) | ||
| {0xb8a5U, 0xb54cU, 0U, 1U, 1U}, | ||
| #ifndef LIBC_TARGET_CPU_HAS_FMA | ||
| // x = -0x1.a34p-1, exp2m1f16(x) = -0x1.bb4p-2 (RZ) | ||
| {0xba8dU, 0xb6edU, 0U, 1U, 1U}, | ||
| #endif | ||
| }}; | ||
|
|
||
| LLVM_LIBC_FUNCTION(float16, exp2m1f16, (float16 x)) { | ||
| using FPBits = fputil::FPBits<float16>; | ||
| FPBits x_bits(x); | ||
|
|
||
| uint16_t x_u = x_bits.uintval(); | ||
| uint16_t x_abs = x_u & 0x7fffU; | ||
|
|
||
| // When |x| <= 2^(-3), or |x| >= 11, or x is NaN. | ||
| if (LIBC_UNLIKELY(x_abs <= 0x3000U || x_abs >= 0x4980U)) { | ||
| // exp2m1(NaN) = NaN | ||
| if (x_bits.is_nan()) { | ||
| if (x_bits.is_signaling_nan()) { | ||
| fputil::raise_except_if_required(FE_INVALID); | ||
| return FPBits::quiet_nan().get_val(); | ||
| } | ||
|
|
||
| return x; | ||
| } | ||
|
|
||
| // When x >= 16. | ||
| if (x_u >= 0x4c00 && x_bits.is_pos()) { | ||
| // exp2m1(+inf) = +inf | ||
| if (x_bits.is_inf()) | ||
| return FPBits::inf().get_val(); | ||
|
|
||
| switch (fputil::quick_get_round()) { | ||
| case FE_TONEAREST: | ||
| case FE_UPWARD: | ||
| fputil::set_errno_if_required(ERANGE); | ||
| fputil::raise_except_if_required(FE_OVERFLOW | FE_INEXACT); | ||
| return FPBits::inf().get_val(); | ||
| default: | ||
| return FPBits::max_normal().get_val(); | ||
| } | ||
| } | ||
|
|
||
| // When x < -11. | ||
| if (x_u > 0xc980U) { | ||
| // exp2m1(-inf) = -1 | ||
| if (x_bits.is_inf()) | ||
| return FPBits::one(Sign::NEG).get_val(); | ||
|
|
||
| // When -12 < x < -11, round(2^x - 1, HP, RN) = -0x1.ffcp-1. | ||
| if (x_u < 0xca00U) | ||
| return fputil::round_result_slightly_down( | ||
| fputil::cast<float16>(-0x1.ffcp-1)); | ||
|
|
||
| // When x <= -12, round(2^x - 1, HP, RN) = -1. | ||
| switch (fputil::quick_get_round()) { | ||
| case FE_TONEAREST: | ||
| case FE_DOWNWARD: | ||
| return FPBits::one(Sign::NEG).get_val(); | ||
| default: | ||
| return -0x1.ffcp-1; | ||
| } | ||
| } | ||
|
|
||
| // When |x| <= 2^(-3). | ||
| if (x_abs <= 0x3000U) { | ||
| if (auto r = EXP2M1F16_EXCEPTS_LO.lookup(x_u); | ||
| LIBC_UNLIKELY(r.has_value())) | ||
| return r.value(); | ||
|
|
||
| float xf = x; | ||
| // Degree-5 minimax polynomial generated by Sollya with the following | ||
| // commands: | ||
| // > display = hexadecimal; | ||
| // > P = fpminimax((2^x - 1)/x, 4, [|SG...|], [-2^-3, 2^-3]); | ||
| // > x * P; | ||
| return fputil::cast<float16>( | ||
| xf * fputil::polyeval(xf, 0x1.62e43p-1f, 0x1.ebfbdep-3f, | ||
| 0x1.c6af88p-5f, 0x1.3b45d6p-7f, | ||
| 0x1.641e7cp-10f)); | ||
| } | ||
| } | ||
|
|
||
| if (auto r = EXP2M1F16_EXCEPTS_HI.lookup(x_u); LIBC_UNLIKELY(r.has_value())) | ||
| return r.value(); | ||
|
|
||
| // exp2(x) = exp2(hi + mid) * exp2(lo) | ||
| auto [exp2_hi_mid, exp2_lo] = exp2_range_reduction(x); | ||
| // exp2m1(x) = exp2(hi + mid) * exp2(lo) - 1 | ||
| return fputil::cast<float16>( | ||
| fputil::multiply_add(exp2_hi_mid, exp2_lo, -1.0f)); | ||
| } | ||
|
|
||
| } // namespace LIBC_NAMESPACE_DECL |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.